Field of Application
This invention relates to the treatment of diseases by raising body temperature; and more particularly to raising the temperature of a specific anatomical portion or portions of a body.
Description of the Prior Art
Hyperthermia as a treatment of tumors has been carefully studied and applied. There appear to have been multiple reports of tumor regression coincident with febrile episodes. Some analysis revealed that body temperatures greater than 41 degree. C. are ordinarily needed to induce tumor necrosis (tumor death). Although, there are multiple methods of inducing hyperthermia by either direct skin contact or radiant heating, many physicians have favored an extracorporeal heat exchange (blood) circuit to raise patient body temperatures. Some patients have been maintained at 41.5 degrees to 42 degrees. C. (rectal temperature) for three to four hours without severe cardiovascular compromise; however, others have suffered elevation of serum transaminases and bilirubin when kept at such temperatures for greater than 10 to 40 minutes. There have also been Instances of neurological damage in association with serum hypophosphatemia, although no significant problems occurred once phosphate levels were maintained. Death may also occur for patients receiving hyperthermia at 41.5 degree. to 42 degree. C. for 1½ to hours, presumably from massive liver tumor necrosis.
U.S. Pat. No. 2,886,771 to Vincent; U.S. Pat. No. 3,482,575 to Claff; U.S. Pat. No. 4,061,141 to Hyden, U.S. Pat. No. 4,191,182 to Popovich; U.S. Pat. No. 4,321,918 to Clark; U.S. Pat. No. 4,322,275 to Jain; U.S. Pat. No. 4,381,004 to Babb; U.S. Pat. No. 4,479,798 to Parks; U.S. Pat. No. 4,540,401 to Marten; U.S. Pat. No. 4,563,170 to Aigner; U.S. Pat. No. 4,576,143 to Clark and U.S. Pat. No. 4,692,188 to Troutner et al.; all relate to methods for the extracorporeal treatment of blood for cancers, viruses and parasites. Tumors are vulnerable to heat and the goal of hyperthermic treatment therapy is to achieve cytotoxic temperatures in the tumor for a sufficient length of time without damaging the surrounding normal tissue. The rate at which blood flows through any given area of tissue determines the amount of heat that may be carried away and therefore is a major determinant of the temperature rise in that tissue. In normal tissue, heat causes vasodilatation. In a tumor, the microvasculature is made up of an overabundance of capillary beds, which are unable to dilate. Blood flow through the area is thus more sluggish and commensurately unable to dissipate heat applied to the area. The inability to respond to heat by dilation, as normal vasculature would, also subjects the tumor to hypoxia, anaerobic metabolism and local acidosis, and these conditions in turn make the tumor tissue more vulnerable to thermal injury.
U.S. Pat. No. 5,354,277 and U.S. Pat. No. 5,476,444 are directed to methods and apparatus for effecting whole-body hyperthermia: however, the equipment and procedures disclosed appear to suffer from relatively difficult temperature controls for the fluid handling systems; possible risk of contamination; and possible difficulty to optimize the fluid handling system for a particular indication.
Some physicians, on the other hand, favor heating only body cavities, such as the peritoneal, and/or chest, cavity with heated fluids to create hyperthermia of the respective tissue surfaces within the cavity. U.S. Pat. No. 6,579,496 and U.S. Pat. No. 6,827,898 appear to be directed to not only body hyperthermia through extracorporal blood heating with circulation of the heated blood through a patient; but also to heating a therapeutic fluid for passage through a regional anatomical area of the body. These patents describe systems which kluge together hospital available equipment such as hemodialysis machines with tubular heat exchangers and high flow positive displacement pumps. The resulting equipment appears to be large and cumbersome, for the task and for the relatively tight hospital quarters for the patient. In addition, the heating of therapeutic fluids, that are to pass through the patient's body, and the passing of such fluids through the patient's body, at such elevated temperatures and flow rates, could be damaging to the patient and even more detrimental to the patient then the disease to be treated.